USC has great financial aid, about 2/3 of students receive some form of it and these numbers are considered high among top-ranking private research universities relative to endowment: http://financialaid.usc.edu/undergraduates/students.html
“In my experience, USC ranks up there with NYU and Boston University”… do you really have experience with several students from each university so that from your experience you can form a ranking? I highly doubt it. If you have a source that ranks universities by “gapping students or loading them up with loans” please provide it.